It is hard to believe that a single photograph can cause such a commotion but when 'It Girl' Alexa Chung posted an innocent looking Instagram picture of herself and her mum, internet warriors suddenly rose up, foaming at the mouth with indignation, decrying what they saw as Chung's excessive thinness and questioning her suitability as a role model.

Chung subsequently made her account private but this did little to quell the rising storm that quickly spilled over into traditional media. What has been almost completely overlooked amidst the furore are two key issues: is it ever right to publicly speculate about an individual's health? And just how complicit are we, the public, when it comes to the despicable art of body snarking whereby we brutally critique the female form?

Firstly: health. Online commentators slammed Chung, threw around accusations of eating disorders and suggested she was using the photo to promote extreme skinniness or thinspiration, an assertion that made her understandably upset. Thinspiration is a disturbing trend where young women spur each other on to achieve extreme thinness. Anyone in their right mind would be horrified to be connected to such carry on, especially someone like Chung, whose popularity is dependent on young women who are fascinated by her style.

The fact of the matter is this: there is one place and one place only to discuss someone's health and that is in private, within the sanctuary offered by family, friends and medical professionals, not on a social media site or on the front of a magazine. Despite what the cult of celebrity may tell us or the manner in which women's bodies are offered up as fresh meat by the media, there are things that should be beyond the realm of public discussion and health is one of them.

Unless an individual chooses to make such information known or the information has a significant direct effect on the public - which is unlikely, unless the person in question is a high ranking politician - then we must remember that health is not a matter for the public sphere and speculating about it is not only misguided but cruel.

While some of the comments in relation to Chung's photograph were reasonable, the vast majority were spiteful, accusatory and invasive, as if someone being in the public eye gives the public carte blanche to make all kinds of obnoxious remarks directly to them. Just how many of those commenting were trained medical professionals with the ability to diagnose someone from behind a screen has yet to be established.

Very thin models are nothing new. Girls who look this way are often richly rewarded and become darlings of the fashion industry that spawned them. There are regular laments about the size of these models and the impact they have on women in general and yet, the skinny staple never seems to change. Why is that?

Fashion is first and foremost a business. If hyper-thin models put consumers off, if we refused to pay for what their bodies help flog, then the industry would be looking for elsewhere for faces quicker than you can say, "pass me that cheeseburger." Despite the public horror at the likes of heroin chic, we still buy into those images by the billion and take our wrath out on the women whose visibility makes them vulnerable: the models and not the people in the boardrooms, pulling the strings.

High profile women and their bodies are fair game for public debate. They are subjected to a level of scrutiny that would render even the most solid individual paranoid. This scrutiny is a magnified version of the type all women face. Our bodies are not truly ours, they things to be observed, picked over and dissected. Can you remember the last time a marauding internet mob demanded a male star with a steroid-induced six pack, "sort himself out"?

We assume it is our right to cast judgement, to make vicious remarks and have an opinion on matters relating to individual women who we know nothing about and yet, are encouraged to tear apart. In the process we hurt other women and we hurt ourselves but here's the thing: it never hurts to be kind and it never hurts to keep your cash for products and companies that celebrate women. As a wise person said many moons ago, "if you don't have anything nice to say, don't say anything at all."